You're currently viewing posts by Pinsider 80spit.
Click here to go back to viewing the entire thread.
I am working on a Stern Galaxy, MPU-200 Having issues with the MPU causing the control lamps to flicker, also I get a reset or a lockup when ball drains to the outhole occasionally, I have narrowed it down to the MPU because it works fine with another board, just would like to get this board up to snuff, voltages are good, just looking for some guidance where to go next
Thanks Guys
Quoted from Quench:Ok, so you're not dealing with battery corrosion.
How about a full frontal picture of the board?
Per the thread I linked above with the same symptom as yours, what does your logic probe indicate at pins 3, 4, 5 and 6 of U15?
Pin 3 low with pulse
Pin 4 both low and high with a pulse
Pin5 low with pulse
Pin 6 low and high with a pulse
It's my understanding pin 4 on U15 should measure 5v, I'm at 2.93v
Quoted from Quench:Without checking a board here, your readings look reasonable.
Pin 4 of U15 should be pulsing which happens upstream via pin 10 of U19.
The output of U15 at pin 3 is called the "VUA-Ø2" signal. It's used for timing when devices on the MPU board are accessed. Check the state of it dowstream at each destination:U10 pin 25
U11 pin 25
U7 pin 10
U7 pin 13
U17 pin 10
Non-banded side of diode CR52
They should all indicate the same as U15 pin 3.
Yes all points test the same. Low with a pulse
Ok, Quench, sorry was away for the weekend, No I do not have a scope, but do have a eprom programmer, more than happy to send you an image.
here are the above results and yes I was on cmos, change to ttl
U17 pin 10 high and low with slow pulse
u17 pin 9 low with pulse
u17 pin 8 high with pulse
u8 pin 19 High with pulse
u13 pin 19 high with pulse
u14 pin 1 high and low fast pulse
u14 pin 2 high with pulse
u14 pin 3 high with pulse
u14 pin 4 high and low no pulse
u14 pin5 high and low no pulse
u14 pin 6 high no pulse
u14 pin7 high no pulse
Thanks
Gerry
Quench
Here are my findings
U14 pins 6 and 7 high with very fast pulse
U14 pins 4 and 5 Low with very fast pulse
u14 pins 3 and 2 High with pulse
U14 pin 1 Low with pulse
My eprom, 2716 check sum is 0001F3DE
Not a pain at all, Thanks for the help
This I believe was the original board for the pin, I think all I did was replace the 5101's to get it to boot, All the control lamps flicker all the time in attract mode and when in game play, reset usually only happens when the ball drains and hits the out hole.
As far as the Roms, I have never tried to read the mask roms, guessing its doable, Ill look into it.
I did try the 000208DE Rom only in U2 left the others in and it booted normally, still the flickering though Ill try posting a youtube video of it
Thanks
Quoted from Quench:If you go into lamp test mode, do the lamps flicker when they flash on?
Are you getting wrong lamps coming on during attract mode / game play?
With your logic probe, what does it indicate at pin 1 on any of the 24 pin chips on the lamp driver board in attract mode? From memory it should be Low with Pulse.
In lamp test mode, they don't appear to flicker, the correct lamps are lighting during game play, pin 1 of the 4 24 pin IC's are low with a pulse
as you thought,
FIXED!!
Andrew, yes I changed out U10, tested fine in the Neoloch , but changed it anyways, no change, got to snooping around with my DVM on diode test and poked around U14 comparing readings to a good board and they were totally off, Socketed it out and put in a new 14572U in and its working perfect,
Thanks to Quench for making me hang in there, Im really no more than a shot gunner doing these boards and was ready to bail, but it was such a clean board, now its ready to go and move this Galaxy out of here to a new owner soon
Quoted from DickHamill:Both problems are fixed (lamps and the reset on trough)?
yup, seems to be working fine, will roll a couple games on it once I get a new speaker in it
Quoted from Quench:Great to hear you found it!
Can you remember which U14 pins were off? May give us a better understanding of the issue.
Ok, Found the old IC took readings again, I had the DVM on diode test, red lead on pin 16, U14 and on a good board all the other pins had a reading between .400 to .700 volts, on the bad IC I got open's on pin 1 thru 6 , pin 11, 13,14, 15
I know this is probably not the right way to check these, but in the past I have found many bad components just using my DVM and comparing it to a known working source, and it worked again one more time
You're currently viewing posts by Pinsider 80spit.
Click here to go back to viewing the entire thread.
Wanna join the discussion? Please sign in to reply to this topic.
Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!
This page was printed from https://pinside.com/pinball/forum/topic/stern-mpu-200-flickering-control-lamps-issue?tu=80spit and we tried optimising it for printing. Some page elements may have been deliberately hidden.
Scan the QR code on the left to jump to the URL this document was printed from.
Morgantown, PA